1. Field of the Invention
This invention relates to transesterified fatty acid esters and the reaction products of a fatty acid ester, in the presence of an acid, with a hydroxyl-containing compound. This composition is useful as a lubricant and as a heat transfer agent, among other uses.
2. Description of the Prior Art
There are a vast number of lubricants and lubricant additives found in the market place today. Many of these lubricants have undesirable compounds for long-term use in a mechanical system. Others exhibit only a limited degree of miscibility in an oil-based system. Common to most of these lubricants is a rather low upper-limit of pressure resistance before the lubricant fails.
U.S. Pat. No. 5,916,854 issued to Inaya et al discloses a biodegradable lubricant base oil. The Inaya biodegradable lubricating base oil is obtained by carrying out an addition reaction of an alkylene oxide and a transesterification in a mixture of fats and oils, a polyhydric alcohol or an aliphatic carboxylic acid and an alkylene oxide. Further, a biodegradable lubricating oil composition containing the biodegradable lubricating base oil and the use thereof are also described. The Inaya patent describes one particular derivative material obtained from fats and oils that shows desired biodegradability and desired stability to thermal oxidation.
It is an object of the current invention to provide a composition and a method of lubricating wherein the lubricant additive is readily miscible in an oil-based system. It is an object of the current invention to provide a composition and a method of lubricating where lubrication is achieved even at low miscibility between the composition and an oil-based system. It is an object of the current invention to provide a lubricant or lubricant additive that is useful at extremely low and extremely high temperature regions. It is an object of the current invention to provide a lubricant or lubricant additive that is useful at extremely high pressures. It is an object of the invention to provide a lubricant or lubricant additive that is not corrosive. It is an object of the invention to provide an additive or working fluid that acts as a corrosion inhibitor.
Fluorinated hydrocarbons have long been used as a refrigerant. In recent years, concern that the fluorinated hydrocarbons are damaging the ozone layer has created a demand for refrigerants that do not deplete the ozone. U.S. Pat. No. 5,976,399 issued to Schnur discloses a blended polyol ester lubricant for refrigerant heat transfer fluids including an ester having neopentylglycol and a source of 2-ethylhexanoic acid as its reactive components. Alternately, an ester having pentaerythritol and a source of 2-ethylhexanoic acid is used. This specific ester was shown to be useful as a lubricant and for a refrigerant heat transfer fluid. Mutual miscibility between the refrigerant and lubricant of the refrigerant working fluid is important to avoid separation of the two.
The closest known methods of performing related functions in the improvement in the energy efficiency of heat pump systems are those including the halogenated a-olefins, the most common of which utilizes the chlorine molecule. (Refer to U.S. Pat. No. 4,963,280) The disadvantage of the chlorine compound is the possibility of a chlorine free radical becoming exposed to moisture resulting in the formation of hydrochloric acid and subsequent corrosion. Additionally, these halogenated compounds are extremely hygroscopic exposing the system to potential moisture contamination.
One of the difficulties experienced using with prior art has been the failure to control the nature of the sludge or deposit and the location of its deposition. Sludges plug lubricating paths and prevent the delivery of an adequate supply of lubricant. Generally, the prior art refers to sludges and deposits as having a high coefficient of friction, low thermal conductivity, ability to readily polymerizes and carbonizes, as being oxidatively unstable and lacking strong adhesive and cohesive properties due to polarity.
It is an object of this invention to provide a method for lubricating surfaces and reducing friction and wear.
It is an object of this invention to allow for the simplification of the mechanical design of machinery and equipment by providing a lubricating method which requires a very simple lubricating means as the reduction in the coefficient of friction.
An object of this invention is to provide a lubricating method wherein there is an automatic supply or replenishment of lubricant to surfaces in friction which acts as a non-insulating and thermally conductive layer while providing heat transfer under low and high loads.
A particular object of this invention is to provide a refrigeration oil lubricant that is compatible with naphthenes, paraffins, alkyl benzenes, mineral oil, polyol esters, polyalphaolefins, polyalkylene glycols, polybutenes and polyvinyl ethers.
It is an object of the current invention to create a heat transfer fluid that does not deplete the ozone. It is an object to develop a composition that acts as a lubricant in a heat exchange fluid. It is the object to develop a composition that acts as an additive but which can also serve as a complete lubricant or working fluid in some cases.
Various objects and mechanical systems are subject to corrosion from working or environmental conditions. Mechanical systems are equipment with moving parts or static physical pieces. It is an object of the current invention to present a composition effective to inhibit corrosion. Similarly, various objects and mechanical systems are susceptible to moisture. It is a further object of the current invention to present a composition effective in inhibiting moisture.
There are numerous fluids that have utility where it is desirable to change the rheological properties of such fluids. Examples of such working fluids include drilling fluids and cutting fluids. Frequently, viscosity is a key property to influence. It is an object of the current invention to present a composition effective to modify the rheological properties of the fluid.
It is an object of this invention to provide a lubricant that is stable at low temperatures, i.e., below 0° C., and elevated temperatures, i.e., above 350° C.
It is an object of this invention to provide a lubricant that possesses boundary lubrication properties.
It is an object of this invention to provide a composition that is highly surface active, hence good detergency.
It is an object of this invention to provide a lubricant that has a low coefficient of friction.
It is an object of this invention to provide a composition which displaces other lubricants that are less polar and substantive than the transesterified fatty acid esters.